Curable liquid polymer compositions

Abstract

This invention relates to a new curable composition which includes a liquid unsaturated component having at least two vinyl addition polymerizable groupings per average molecule and a polythiol component having a multiplicity of -SH functional groups per average molecule which cures to a solid polythioether in the presence of a free radical generator. When the free radical generator is actinic radiation, e.g. U. V. light, a photocuring rate accelerator, e.g. benzophenone is added to the composition. The cured product can be used as a coating, sealant, adhesive or molded article.

What is claimed is: 
     
       1. A composition curable in the presence of a free radical generating agent comprising: I. 98 to 2% by weight of the composition of a liquid polyene component of the formula   [A--X).sub.m     wherein m is an integer of at least 2, X is ##STR12## and A is a polyvalent organic moiety, free of reactive carbon to carbon unsaturation and of highly water-sensitive members and consisting of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, chlorine, bromine, fluorine, phosphorous and silicon; and R is a radical selected from the group consisting of hydrogen, phenyl and an alkyl containing 1 to 9 carbon atoms; and,     Ii. 2 to 98% by weight of the composition of a polythiol having a molecular weight in the range from about 95 to 20,000 of the general formula:   R.sub.8 --SH).sub.n     wherein R 8  is a polyvalent organic moiety and n is at least 2, the reactive unsaturated carbon to carbon bonds per molecule in the polyene and the thiol groups per molecule in the polythiol being greater than 4.     
     
     
       2. The composition of claim 1 including 0.0005 to about 50% by weight of the polyene/polythiol composition of a photocuring rate accelerator. 
     
     
       3. The composition of claim 1 wherein the polyene is a member of the group consisting of methylene bisacrylamide 1,3 butylene glycol diacrylate, 1,4 butylene glycol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, 1,6-hexane diol diacrylate, pentaerythritol tetraacrylate, bisphenol A dimethacrylate, N,N'-di(hydroxyethyl)dimethylhydantoin diacrylate, polyethylene glycol (200)diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, bisphenol A diacrylate, 1,3 butylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and trimethylol propane trimethacrylate, trimethylolpropane tricrotonate, and diethylene glycol dicinnamate. 
     
     
       4. The composition according to claim 1 wherein the polyene is the reaction product of an isocyanate terminated prepolymer or isocyanate monomer with a hydroxyalkyl ester of a member of the group consisting of acrylic acid, methacrylic acid, crotonic acid and cinnamic acid. 
     
     
       5. The composition according to claim 1 wherein the polyene is the reaction product of an oxirane terminated epoxy resin with a member of the group consisting of anhydride, acrylhalide amide and hydroxyalkyl ester of an acid member of the group consisting of acrylic, methacrylic, crotonic anc cinnamic. 
     
     
       6. A process of forming a solid cured polythioether which comprises 1. admixing a composition comprising: I. 98 to 2% by weight of the composition of a liquid polyene component of the formula   [A--X).sub.m     wherein m is an integer of at least 2, X is ##STR13## and A is a polyvalent organic moiety free of reactive carbon to carbon unsaturation and of highly water-sensitive members and consisting of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, chlorine, bromine, fluorine, phosphorous and silicon; and R is a radical selected from the group consisting of hydrogen, phenyl and an alkyl containing 1 to 9 carbon atoms;     Ii. 2 to 98% by weight of the composition of a polythiol having a molecular weight in the range from about 94 to 20,000 of the general formula:   R.sub.8 --SH).sub.n     wherein R 8  is a polyvalent organic moiety and n is at least 2, the reactive unsaturated carbon to carbon bonds per molecule in the polyene and the thiol groups per molecule in the polythiol being greater than 4, and       
     
     
       2. exposing the mixture to a free radical generating agent. 
     
     
       7. The process according to claim 6 wherein the free radical generating agent is high energy radiation. 
     
     
       8. The process according to claim 6 wherein the free radical generating agent is a chemical free radical generating agent. 
     
     
       9. The process of claim 8 wherein the chemical free radical generating agent is selected from the group consisting of molecular oxygen; organic hydroperoxides and peroxides; blends of organic hydroperoxides and peroxides with tertiary amines; blends of organic hydroperoxies and peroxides with transition metal salts and blends of organic hydroperoxides and peroxides with tertiary amines and transition metal salts. 
     
     
       10. The process according to claim 6 wherein the composition includes 0.0005 to about 50% by weight of the polyene/polythiol composition of a photocuring rate accelerator. 
     
     
       11. The process according to claim 10 wherein the free radical generating agent is U. V. light. 
     
     
       12. The process according to claim 6 wherein the polyene is a member of the group consisting of methylene bisacrylamide 1,3 butylene glycol diacrylate, 1,4 butylene glycol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, 1,6-hexane diol diacrylate pentaerythritol tetraacrylate, bisphenol A dimethacrylate, N,N'-di(hydroxyethyl)dimethylhydantoin diacrylate, polyethylene glycol (200)diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, bisphenol A diacrylate, 1,3 butylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and trimethylol propane trimethacrylate, trimethylolpropane tricrotonate, and diethylene glycol dicinnamate. 
     
     
       13. The solid polythioether product prepared by the process of claim 6. 
     
     
       14. A sealant consisting essentially of the composition of claim 1. 
     
     
       15. An adhesive consisting essentially of the composition of claim 1. 
     
     
       16. The composition of claim 1 where X is acryloxy or methacryloxy. 
     
     
       17. The composition of claim 16 wherein X is acryloxy. 
     
     
       18. A composition capable of being crosslinked solely by radiation to form thioether groups between the carbon-to-carbon unsaturation of I and the thiol groups of II comprising: I. 98 to 2% by weight of the composition of a liquid polyene component of the formula   [A--X).sub.m     wherein m is an integer of at least 2, X is ##STR14## and A is a polyvalent organic moiety, free of reactive carbon to carbon unsaturation and of highly water-sensitive members and consisting of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, chlorine, bromine, fluorine, phosphorous and silicon; and R is a radical selected from the group consisting of hydrogen, phenyl and an alkyl containing 1 to 9 carbon atoms; and,     Ii. 2 to 98% by weight of the composition of a polythiol having a molecular weight in the range from about 95 to 20,000 of the general formula:   R.sub.8 --SH).sub.n     wherein R 8  is a polyvalent organic moiety and n is at least 2, the reactive unsaturated carbon to carbon bonds per molecule in the polyene and the thiol groups per molecule in the polythiol being greater than 4.     
     
     
       19. A process of forming a solid cured polythioether which consists essentially of 1. admixing a composition consisting essentially of: I. 98 to 2% by weight of the composition of a liquid polyene component of the formula   [A--X).sub.m     wherein m is an integer of at least 2, X is ##STR15## and A is a polyvalent organic moiety free of reactive carbon to carbon unsaturation and of highly water-sensitive members and consisting of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, chlorine, bromine, fluorine, phosphorous and silocon; and R is a radical selected from the group consisting of hydrogen, phenyl and an alkyl containing 1 to 9 carbon atoms;     Ii. 2 to 98% by weight of the composition of a polythiol having a molecular weight in the range from about 94 to 20,000 of the general formula:   R.sub.8 --SH).sub.n     wherein R 8  is a polyvalent organic moiety and n is at least 2, the reactive unsaturated carbon to carbon bonds per molecule in the polyene and the thiol groups per molecule in the polythiol being greater than 4, and       
     
     
       2. exposing the mixture to a free radical generating agent.